10.5 HAL (Lead-Free/Leaded)

FeatureDescription / Value
Application
  • Soldering
  • Press-fit technology
Properties
  • High thermal load on the PCB (240 - 280 °C)
  • Uneven layer thickness distribution
    on the surface and in the holes depending on the layout
  • Solder mask webs recommended to avoid tin bridges
Properties of lead-free HAL
  • RoHS compliant
Properties of leaded HAL
  • 37/63 % SnPb alloy
  • NOT RoHS compliant!
Plating thickness [µm]Surface: 1 - 30
Hole < 3.0 mm: 1 - 50
Hole ≥ 3.0 mm: 1 - 70
Processing warranty in months
(at a max. storage temperature of 30°C and max. relative humidity of 70%)		12
Not to be used on
  • Exposed lettering and pads in copper surfaces
  • Microvias, blind vias, BGAs
  • Rigid-flex and HSMtec PCB´s
  • FR4 materials with a Tg ≤ 135 °C
  • Base copper thickness ≥ 105 µm and
    sum of all copper layers ≥ 420 µm
Not recommended for
  • PCB final thickness < 0.80 mm
  • PCB final thickness > 2.40 mm

Wetting problems with insufficient Font-weight in Copper areas

Perfect tin wetting of lettering on copper areas can only be guaranteed with a font-weight of at least 300 µm!

Wetting problems of SMD pads in copper surfaces

Perfect tin wetting of such SMD pads fully connected in larger copper surfaces with the HAL (Hot Air Leveling) surface is not always guaranteed! The reason lies in the thermal behaviour of such SMD pads, as the heat introduced by the HAL (Hot Air Leveling) process is quickly conducted (spread) into the copper area, making it difficult for these SMD pads to reach temperature!
*) Design proposal for Thermal pads, if there are no other special requirements.
The four connections should be rotated by 45°.

Frequently asked questions

Do I have to use an FR4 material with the maximum Td (Td = decay temperature) for lead-free soldering?
A higher Td value is recommended, especially for a technically complex PCB that will undergo a series of soldering operations. However, this can lead to higher costs. The more you can tell us about the assembly, the easier it will be to make the right decision.

Keywords

  • Hot air solder leveling (HASL)
  • Lead-free HASL
  • Wetting
  • Surface finishes
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10.6 OSP
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